Screening models for antiulcer drugs MCQs With Answer

Introduction: Screening models for antiulcer drugs are essential in experimental pharmacology for B.Pharm students to understand drug discovery and evaluation. These models—such as pylorus ligation, ethanol-induced, NSAID-induced (indomethacin), acetic acid-induced chronic ulcer, stress-induced and cysteamine-induced duodenal ulcer—help assess antisecretory and cytoprotective actions, ulcer index, gastric acidity, mucosal blood flow, and biomarkers (mucin, GSH, MPO, SOD). Familiarity with in vivo and in vitro assays, H+/K+ ATPase inhibition, choice of positive controls (omeprazole, ranitidine, misoprostol), dose selection, and ethical considerations improves study design and interpretation. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which animal model is classically used for evaluating antisecretory activity by measuring gastric juice volume and acidity?

• Pylorus ligation (Shay rat) model
• Ethanol-induced gastric ulcer model
• Acetic acid-induced chronic ulcer model
• Cold restraint stress model

Correct Answer: Pylorus ligation (Shay rat) model

Q2. The ethanol-induced gastric ulcer model primarily evaluates which property of an antiulcer agent?

• Antisecretory activity
• Cytoprotective and mucosal barrier protection
• Antimicrobial activity against H. pylori
• Prokinetic activity

Correct Answer: Cytoprotective and mucosal barrier protection

Q3. Indomethacin-induced ulcers in rats are used to model ulcers caused by which human drug class?

• Beta blockers
• Nonsteroidal anti-inflammatory drugs (NSAIDs)
• Proton pump inhibitors
• Anticoagulants

Correct Answer: Nonsteroidal anti-inflammatory drugs (NSAIDs)

Q4. Which chronic ulcer model is most suitable for studying ulcer healing and scarring processes?

• Pylorus ligation model
• Acetic acid-induced chronic ulcer model
• Ethanol-induced acute ulcer model
• Cold water immersion stress model

Correct Answer: Acetic acid-induced chronic ulcer model

Q5. Which parameter is commonly used to express lesion severity in experimental ulcer models?

• Ulcer index
• Mean arterial pressure
• LD50
• Renal clearance

Correct Answer: Ulcer index

Q6. Which biochemical marker indicates oxidative stress in gastric mucosa following ulcer induction?

• Serum creatinine
• Reduced glutathione (GSH) depletion
• Plasma glucose elevation
• Serum albumin increase

Correct Answer: Reduced glutathione (GSH) depletion

Q7. Which standard drug is commonly used as a positive control for antisecretory activity in animal models?

• Misoprostol
• Omeprazole
• Sucralfate
• Activated charcoal

Correct Answer: Omeprazole

Q8. Sucralfate provides ulcer protection primarily by which mechanism?

• H+/K+ ATPase inhibition
• Forming a protective physical barrier over the ulcer
• Antimicrobial action against H. pylori
• Stimulating gastric acid secretion

Correct Answer: Forming a protective physical barrier over the ulcer

Q9. Which assay directly assesses inhibition of gastric H+/K+ ATPase in vitro?

• Ulcer index calculation
• ATPase enzyme activity assay
• MPO activity in mucosa
• Gastric mucin quantification

Correct Answer: ATPase enzyme activity assay

Q10. Which experimental model is most appropriate to test anti-H. pylori activity of a candidate compound?

• In vitro bacterial culture and MIC determination
• Pylorus ligation in rats
• Ethanol-induced ulcer in mice
• Acetic acid chronic ulcer in rats

Correct Answer: In vitro bacterial culture and MIC determination

Q11. In pylorus ligation experiments, fasting of animals is required to:

• Prevent hypothermia during surgery
• Reduce interference from food on gastric secretion measurements
• Increase body weight
• Induce H. pylori infection

Correct Answer: Reduce interference from food on gastric secretion measurements

Q12. Misoprostol is used as a reference drug in NSAID-ulcer models because it is a:

• Proton pump inhibitor
• Prostaglandin E1 analog with cytoprotective effects
• H2 receptor antagonist
• Pepsin inhibitor

Correct Answer: Prostaglandin E1 analog with cytoprotective effects

Q13. Which marker is commonly measured to assess neutrophil infiltration in gastric tissue?

• Glutathione peroxidase
• Myeloperoxidase (MPO) activity
• Alkaline phosphatase
• Creatine kinase

Correct Answer: Myeloperoxidase (MPO) activity

Q14. Cold restraint stress model induces ulcers mainly via:

• Direct chemical mucosal necrosis
• Enhanced gastric acid secretion and reduced mucosal blood flow
• H. pylori colonization
• Enzyme inhibition of H+/K+ ATPase

Correct Answer: Enhanced gastric acid secretion and reduced mucosal blood flow

Q15. The ulcer index formula often combines which of the following measurements?

• Ulcer number, ulcer severity/score, and lesion area
• Serum ALT and AST levels
• Animal weight and food intake
• Blood pressure and heart rate

Correct Answer: Ulcer number, ulcer severity/score, and lesion area

Q16. Which advantage does the acetic acid-induced chronic ulcer model have over ethanol-induced model?

• Produces rapid, reversible lesions only
• Better simulates chronic human ulcer healing and fibrosis
• Does not require anesthesia
• Is primarily used for antisecretory testing

Correct Answer: Better simulates chronic human ulcer healing and fibrosis

Q17. When testing a new antiulcer agent, selecting an appropriate positive control is important because:

• It increases animal mortality
• It provides a benchmark to compare efficacy and validates the model
• It eliminates the need for a vehicle control
• It shortens the fasting period

Correct Answer: It provides a benchmark to compare efficacy and validates the model

Q18. Which parameter indicates increased gastric acidity in pylorus ligation studies?

• Increased gastric juice pH
• Increased total acidity and reduced pH
• Increased gastric mucin concentration
• Decreased pepsin activity

Correct Answer: Increased total acidity and reduced pH

Q19. Which outcome supports a cytoprotective mechanism rather than antisecretory effect?

• Decrease in gastric juice volume
• No change in acid output but increased mucin and mucus thickness
• Marked inhibition of H+/K+ ATPase
• Significant rise in gastric pH

Correct Answer: No change in acid output but increased mucin and mucus thickness

Q20. Ethical considerations in antiulcer screening include all except:

• Using the minimum number of animals required to achieve statistical power
• Applying humane endpoints and analgesia when needed
• Randomization and blinding to reduce bias
• Deliberately causing unnecessary pain for demonstration purposes

Correct Answer: Deliberately causing unnecessary pain for demonstration purposes

Q21. Cysteamine-induced ulcers are used to model which type of ulceration?

• Drug-induced gastric ulcers
• Duodenal ulcers with increased acid secretion
• Stress-related mucosal damage only
• H. pylori-associated ulcers exclusively

Correct Answer: Duodenal ulcers with increased acid secretion

Q22. Which histological feature is indicative of healing in chronic ulcer models?

• Persistent necrosis and deeper mucosal damage
• Epithelial regeneration and collagen deposition (fibrosis)
• Increased neutrophil infiltration
• Enlarged ulcer crater with hemorrhage

Correct Answer: Epithelial regeneration and collagen deposition (fibrosis)

Q23. For in vivo antiulcer screening, which species is most commonly used?

• Rats and mice
• Cats and dogs
• Nonhuman primates only
• Fish models exclusively

Correct Answer: Rats and mice

Q24. Which biochemical assay measures antioxidant enzyme activity relevant to ulcer protection?

• Myeloperoxidase (MPO) only
• Superoxide dismutase (SOD) and catalase assays
• Serum urea measurement
• Blood glucose assay

Correct Answer: Superoxide dismutase (SOD) and catalase assays

Q25. In designing dose-response studies for antiulcer agents, which approach is appropriate?

• Use a single arbitrarily chosen dose
• Test multiple doses including sub-therapeutic, therapeutic, and supra-therapeutic ranges
• Avoid including a vehicle control
• Only compare two animals per group

Correct Answer: Test multiple doses including sub-therapeutic, therapeutic, and supra-therapeutic ranges

Q26. Which of the following is NOT a typical endpoint in antiulcer screening studies?

• Ulcer index or lesion scoring
• Gastric juice pH and acidity
• Histopathological scoring of mucosal healing
• Electrocardiogram QT interval in conscious animals

Correct Answer: Electrocardiogram QT interval in conscious animals

Q27. A reduction in mucosal prostaglandin levels is commonly associated with ulceration caused by:

• Prostaglandin analogs
• NSAIDs like indomethacin
• Proton pump inhibitors
• Sucralfate treatment

Correct Answer: NSAIDs like indomethacin

Q28. Which experimental change would most likely confound results in an ethanol-induced ulcer study?

• Standardized timing and dose of ethanol
• Using animals with variable fasting times
• Blinding the observer assessing lesions
• Including a vehicle control group

Correct Answer: Using animals with variable fasting times

Q29. Combining antisecretory and cytoprotective assessment in one study can be achieved by:

• Measuring only gastric pH
• Assessing acid output plus mucin content and histology
• Using only in vitro H+/K+ ATPase assay
• Skipping biochemical assays

Correct Answer: Assessing acid output plus mucin content and histology

Q30. Statistical analysis in antiulcer screening should include which of the following practices?

• No statistical tests are needed for biological data
• Predefining endpoints, using appropriate tests, and reporting P values and confidence intervals
• Only reporting mean values without variability measures
• Choosing statistical tests after looking at the data outcome

Correct Answer: Predefining endpoints, using appropriate tests, and reporting P values and confidence intervals

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